Morphological filters based on motif combination for functional surface evaluation

Regarded as the complement of commonly used mean-line based filters, morphological filters are more function oriented. They are relevant to geometrical properties of surfaces and provide better results for functional evaluation of surfaces. The paper first gives a brief introduction to morphological filters. An algorithm to implement morphological filters is proposed, which is based on the motif combination. Experimental data are presented to illustrate the algorithm´s superiority in performance. The end effect of morphological filters is corrected by the reflective padding. Either circular or horizontal structuring element is available using this method. Two examples of applying the morphological closing filter with the disk and the line-segment structuring element on a milled surface profile are illustrated. Finally, the morphological alternating sequential filter is employed to evaluate the roughness of functional stratified surfaces as a replacement to the two-stage Gaussian filter.